Variable friction gearing



March 22, 1932- J. H. ROBERTSON VARIABLE FRICTION GEARING 3 Sheets-Sheet Filed Dec. 2, 1929 ..//l INN A.

March 22, 1932. n J2 H ROBERTSON VARIABLE FRICTION GEARING s sheets-sheet 2 Filed Dec. 2, 1929 mmm March 22, 1932. J. H. ROBERTSON VARIABLE FRICTION GEARING' Filed Dec. 2. 1929 3 Sheets-Sheet 3 Patented Mar.Y 2.2,A 1932 Unirse' Simms PATENT, g:oF-HCE JOHN 4Hoen; RoBnn'rson-*orronnolm nncmmn Y VARIABLE 'FR-Iconen :inname Applicatniled December `2, 1929, Seria1:No. 4111,095, adiinGreatBritain December 19, 517928.

This invention relates to variable -friction.

gearing in which a drivenmember is adapted to make `facecontact -With adriving member, a--direct drive position bemgiprcvided in which the two members engage coaXially .ink

the mannerof a disc orV cone clutch, yand a series of indirect drivefpositionsbeing provided in which one member is displacedlaterally to av variable extent so that contact `takes place y eccentrically between i the conical surfaces of the'two,A members-atfpoints (or limited area-s) of which therafdial'A distances from the respective airesareunequal.

In my Patent 1,772,593 grantedunder date of August 12, 1930, I haveidescribed a variable friction gearing in which the driving and driven members are `controlled automatically in accordance withthe speedand/or load,and the laterally displaceable member is also displaceable axially /by'an independent regulating device, so fthat the automatic operation 'of the vvari'able'gear:can be su pressed or modiiedto suitfparticular-'condiitions of oper-ation. ,Y The present invention` has 'for itsfmainf object'to provide an improved arrangement of the parts in a frictiongearing of thea-beve type, and it comprises lmeans whereby the other :Erictional member. `with which ,the `laterally displaceable member-engages can lbe displaced axially, not only automatically Xin accordance with the speedfor other function, but also by an independent regulatingcontrol, so that'the resultant displacement isdetermined by thecombination or theautomatic and the independent controls. n

The invention Vhas "for its especial object the application of the variable-friction gearing to small shunting locomotives landthe like, in which it isi desirable.tojprecludey any creeping of the locomotive Whenthe engine is `idling or running slowly, .to ensure that the accidental acceleration ofI the engine from the slow-running speed will not movethe locomotive inopportunelyrand also yto furnish means for regulating the rate of .acceleration for varying conditions. without altering the norm-alV automatic action .of the gearing.

trol or to separate theffriction kmembers suf- .o`f construction. j fr .the axially displaceable driving member c,

`In the .preferred arrangement, fthe driven.

,junction therewitlntthe driving member can be given, for examplejmanually, .an independent. axial displacement, so asfto :increase or-to decrease the amountof .its axial displacementy as producedautomatically by .the governor device, theelect beingto varythe range ofigear afforded bythe automaticconciently .to prevent their engagementwith one another. f

, .Theinvention is hereafter described-with reference Ito .the accomp anying; drawings, in

which: l n 70 Figure v ly .represents in' sectional elevation,

a variable vfriction gearing vembodying the present .imp'rok'vementsl y' Iigureis ay similarzvievv off a second cforni Figure `3 is an end view'ofFigure `2.'

4The'fdriving member a ofthefriction gearingshown in F igurel vis mounted together withits governor device b, which controls its n axial displacement in accordance with the l: speednpon an axially slidable shaft c forming ja prolongation ,ofthe engine shaft-or driving :shaft d, Ithe -Slidable shaft lcfbeingV 4regulated in Aposition by a hand lever ezprovided vvith'alatchc1 Wokingovera quadrantf. "The slidable-shaft c is connectedat one end to the shaft dby a telescopicl driving joint, such as a splined connection-g; its other end, which carries the governor device bg'an'd nu is supportedby a travelling roller bearing h "inside a bell'housing r'Korthe'vlilie, arthrfst bearing collar uponfthe slidablepshalftga -beingcontrolled by the hand-lever e.

The centrifugal,governor weigl'its kli'r( of "c5 whichy lonly* one y is shown)` `are'pivotally mounted upony lspindles 7a2 'carriedby `a ring la bolted to a flange c1 at the end of the shaft,

which is formed as `a cylindrical socketin vwhichdshehub al of the'drivingfdisc'is slid- P00 able. The drive may be transmitted to the disc a by a splined or like connection between Y the socket and the hub al, or by means of the studs a2 which slide throughr bushes in the ring c and carry the cover b1 enclosing the governor device b. The back of the disc a is suitablyshaped to engage the edges of the governor weights k1 which are formed as cams ,703 to produce the desired axial displacement of the disc according to itsspeed of rotation.

The driven member of the friction gearing comprises a wheel Z secured to the shaft fm, the wheel engaging the driving disc a through the medium of a loose concentric disc n fitted with friction material al, a2 on its opposite sides. The driven shaft m is supported by a radius arm 0 which swings upon a spindle p rotatably mounted in bearings p1, p2 upon the frame g, the radius arm being adapted to slide along the spindle 29 until arrested by a stop screw 01 abutting against the end p3 of the spindle by the action of an adjustable spring r serving to limit the pressure between the frictional members when in engagement. The radius arm o also comprises a part-circular housing 02 which covers in the driven member of the friction gearing.

The driven shaft m is fitted with a imiversal joint connection m1 for transmitting the i'inal drive to a propeller shaft or the like (not shown).

With this arrangement, the driven niember Z has only to perform its movement of lateral displacement together with such axial displacement as is necessary to maintain its contact with the driving member a, but it is not subjected to the supplementary axial displacement due to the independent regulating control exerted by the hand lever, as in my prior application mentioned; consequently a reverse gear or equivalent, if required, can be mounted in direct relation to thev driven member, the reverse gear box being shown Varranged as at 03' integral with the radius arm 0 which supports the driven member. `The engagement of the reverse gear can be controlled for example by a Bowden cable device e?, operated by a catch (not shown) upon the hand lever c, which can thus be conveniently operated for interrupting the friction drive while the reverse is being engaged or disengaged by the same hand. In addition to or instead of the reverse gear mentioned, there might be provided a low gear drive through a reducing train or through a separate gear box, for use in particularly arduous conditions.

Figures 2 and 3 illustrate another forni of construction in which the drive is transmitted through a reducing train enclosed in the radius arm.

In this construction, the driving member a3 of the friction gearing is mounted upon the end of an axially slidable shaft 02 having its other end connected by a telescopic oint g1 to the engine shaft or driving shaft d1. At about the middle of its length, the shaft c1 carries a plate c3 the back of which is suitably shaped to engage the cam-shaped edges of the governor weights 7a4; the support for the governor weights is in Vthis construction formed as a flange s1 upon a sleeve s surrounding the shaft c2 and slidable along the latter. A hand lever e2 controls a thrust collar s2 mounted upon the other end of the sleeve s, a compression spring r1 being fitted around the sleeve s between the flange s1 and the collar s2 which is slidable along the sleeve against the compression of the spring. The operation of the hand lever in one direction will draw baclr the governor from the plate c3, so that a higher speed of the driving shaft all will be required to bring the governor weights 7L* up against the plate for starting,

in the opposite direction will act through the i spring r1 to advance the governor towards the plate c3, giving a higher gear ratio; if the friction gear is already at the highest ratio or direct-drive position, the spring r1 will take up the movement of the hand lever without shifting the slidable shaft c2, the pressure on the plate ,c3 and at the friction driving surfaces being increased accordingly.

In this construction the driven member Z1 jand driven shaft m2 are carried by the upper end of a radius arm o4 which swings about the center of a laysliaft t; in Figure 3, the full lines indicate the position of the radius arm 04 corresponding to the high gear position, with the friction members in coaxial relation, while the dotted lines indicate the low gear position, with the driven member displaced laterally to the full extent. Since the layshafttforms the center of the swinging4 movement of the radius arm, it can transmit the final drive through bevel gears a al for example to a final drive shaft or vehicle axle fu asshown in Figure 2.

The radius arm 04 is pivotallyv mounted in a bearing bracket t1 extending from the vcasing @l and supporting the shaft t, so that the radius arm swings concentric-all latter.

y of the The drive :troni the shaft mis coin-- municated to the shaft t by means of 'w w1 L02 enclosed inthe radius arm. which constitutes a casing for these gears, of which the intermediate gear wl runs idly upon a fixed axle 'w3 while the relative diameters of the two gears fw @U2 are selected according to the reduction of speed to be effected between the shafts m2 and towhich they are respecy tively secured.

The upper end of the radius arm is shown provided With a roller w carried by a forked bracket w1 forming a cover over the free end of the shaft m2; this roller travels upon yan arcuate guide rail e fixed upon the frame of the vehicle or the like, so that the end thrust of the friction members is borne by the roller a: directly in line With the driven shaft m2.

Vhat I claim is 1. In a variable friction gearing, comprising driving and driven members Withconical and an independentmaiiual control for theY axial displacementof said other member.

2. In a variable friction gearing, 4comprising driving and driven members with conical f surfaces adapted for frictional driving contact, said members having their axes of'rotation substantially parallel, said driving meniber being displaceable axially to maintain contact With` said driven member, an automatic governor-controlled mechanism for regulating the axial displacement of said driving member, and said driven member being displaceable laterally from a position coaxial With said driving member to an eccenf tric position, and means for regulating the axial displacement of said driving member by an independent control superposed upon the automatic control.

3. In a variable friction gearing, comprising driving and driven members With conical "u surfaces adapted forfrictional driving contact, said members having their axesof rotation substantially parallel, said driving member being displaceable axially to maintain contact With said driven member, an auto-y matic governor-controlled mechanism for regulating the axial displacement of said driving member, and said driven member being displaceable laterally from a position coaxial vvith said driving member to an eccentric position, the combination of a slidable shaft connected for rotary movement to said driving member, said rshaft having said governor-controlled mechanism mounted thereon, a tlirust-collar mounted upon said slidable shaft, and manual means in connection With said thrust collar for producing axial movement of said slidable shaft.

4. A variable friction gearing, comprising driving and driven members with conical surfaces adapted for frictional driving Contact,

`sai-'d members having'ftheir axes-,of rotation substantially parallel, fa yradius Iarm'supportdfn'gfone ofsai-d memberszfor lateral disp-lacement to a positioneccefntriciof the other member, axial-Hy slidable shaft connected for 'rotary :movement to said'otjher memberya governor mechanism mounted upon ksaid the position of said 'slidable shaft.

5. A variable friction gearing, comprising driving and 'driven members With conical :sur:-

-faces adapted for frictional driving Contact,

said members having their axes y'off rotation substantial-ly parallel, a radius arm supportinfg said drivenmember for lateral displacement vto a' position eccentric Vof said driving member, va driving shaft, Ian axially slidable shaft connecting said driving shaft to said driving member, said driving member being displaceable axially in relation to said slid- :able shaft,fautomatic 'means for controlling thev displacement of saidv driving member inrelation vto said slidable shaft,-and independen't means for regulating the position of 6. Afvariable friction gearing, comprising driving and driven members With conical surfacesadapted for `frictionafl driving contact, a vradius larm'supporting said driven member `for lateral. displacement to a position eccentric of said driving member, a driving shaft, an kaxially rsl-icviable shaft connecting said driving shaft to said driving member, a frame, means for supporting said slidable shaft in said frame, a spindle mounted in said frame and carryingasaid radius arm, a gov-r ernor mechanism mounted upon said slidable shaft and controlling automatically the axial displacement of said driving member in relavtion thereto, and independent controlling means arranged upon said frame for producing axial displacement of said slidable shaft and said governor mechanism, whereby said driving member receives a resultant axial displacement due to the combination of the automatic and the independent controls.

- 7. A variable friction gearing, comprising driving and driven members With conical surfaces adapted for frictional driving contact, said members having their axes of rotation substantially parallel, a radius arm support-Y ing said driven member for lateral displaceshaft, Vfsaidgovernor mechanism y'adaptedto f produ-ce axial displacement Vof said otherY member in accordance iviith' the speed of said shaft, aend independent means for regulating mentto a position eccentric of said driving member, a driving shaft, an axially slidable shaft connecting said driving shaft to'said driving member, said driving member beslidable shaft, automatic means for controlling the displacement of said driving member in relation to said slidable shaft, a driven '.125 ing displaceable axiallyin relation to saidy shaft journaled in said radius arm, a supple-W13@ LTDS mentary gear box embodied in saidradius arm for transmitting power from said driven member to said driven shaft, and manual means for controlling the position of said slidable shaft whereby said driving member receives a resultant axial displacement due to the combination of the automatica-nd the manual controls while said driven member, said driven shaft and said gear box move laterally with said radius arm.

8. A variable friction gearing, comprising driving and driven members with conical surfaces adapted for frictional driving contact, a radius arm supporting said driven member for lateral displacement to a position eccentric of said driving member, a driving shaft, an axially slidable shaft connecting said driving shaft to said driving member, a frame, means for supporting said slidable shaft in said frame, a spindle mounted in said frame and carrying said radius arm, a governor mechanism mounted upon said slidable shaft and controlling automatically the axial displacement of said driving member in relation thereto, manual controlling means for producing axial displacement of said slidable shaft: and said governor mechanism, and spring means opposing the movement of said manual controlling means towards increased axial displacement of said driving member and limiting the advance of said driving member in relation to said driven member.

In testimony whereof I have affixed my signature.

JOHN HOGG ROBERTSON. 

